The present invention relates to an apparatus for positioning a patient-support deck and particularly, to an apparatus that moves a patient-support deck longitudinally relative to a base of a patient-support device. More particularly, the present invention relates to an apparatus for longitudinally moving a patient-support deck to facilitate taking x-ray or fluoroscopic images of a patient resting on a mattress supported by the patient-support deck.
Many conventional patient-support devices, such as operating tables and imaging tables, have mechanisms that are used to move a patient-support deck of the device longitudinally relative to a base of the device. Such adjustments in the longitudinal position of the patient-support deck may be made so that x-rays or fluoroscopic images can be taken of a patient supported by the patient-support deck. Some X-ray devices and other types of imaging devices have C-arms that are movable to positions having portions of the C-arm above and below the patient-support deck. Thus, it is desirable for patient-support devices to have a minimum amount of structure in the area beneath the patient-support deck to minimize the interference of the structure with the C-arm.
In accordance with one embodiment of the present invention, a patient-support apparatus includes a base, a patient-support deck that has a longitudinal length and a transverse width, and a deck-positioning assembly coupling the patient-support deck to the base. The patient-support deck is supported with respect to the deck-positioning assembly for longitudinal movement. Additionally, the deck-positioning assembly includes an actuator having a first portion and a second portion that moves transversely relative to the first portion. Furthermore, the deck-positioning assembly includes a transmission assembly configured to convert transverse movement of the second portion relative to the first portion into longitudinal movement of the patient-support deck relative to the base.
In preferred embodiments, the actuator is a linear actuator, such as a hydraulic cylinder, and the second portion moves axially along a first transverse axis relative to the first portion. Also in preferred embodiments, the transmission assembly includes a threaded shaft and a ball nut coupled to the threaded shaft. The threaded shaft is rotatable about a second transverse axis and the linear actuator is coupled to the ball nut so that extension and retraction of the second portion of the linear actuator relative to the first portion moves the ball nut along the threaded shaft which causes the threaded shaft to rotate. Also in preferred embodiments, the transmission assembly includes a pinion coupled to the threaded shaft and a rack coupled to the patient-support deck. The pinion engages the rack such that rotation of the threaded shaft and pinion causes longitudinal movement of the rack and patient-support deck relative to the base.
In accordance with another embodiment of the present invention, a patient-support apparatus includes a base, a patient-support deck having a longitudinal length and a transverse width, and a deck-positioning assembly coupling the patient-support deck to the base. The patient-support deck is supported with respect to the deck-positioning assembly for longitudinal movement. The deck-positioning assembly includes a shaft rotatable about a transverse axis between a first position and a second position. A rack is coupled to the patient-support deck and a lock assembly is coupled to the shaft. The lock assembly includes a member that moves in response to rotation of the shaft. The member engages the rack when the shaft is in the first position to prevent longitudinal movement of the patient-support deck relative to the base. The member is disengaged from the rack when the shaft is in the second position to allow longitudinal movement of the patient-support deck relative to the base.
In preferred embodiments, an actuator, such as an electric solenoid, is provided for moving the shaft between the first and second positions. Also in preferred embodiments, the member of the lock assembly is a pawl. One preferred lock assembly includes a cam coupled to the shaft and engaging the pawl so that rotation of the shaft rotates the cam to move the pawl into and out of engagement with the rack. After the lock assembly is unlocked, the patient-support deck is manually movable relative to the base. Also in preferred embodiments, an angle sensor is coupled to the deck positioning assembly. If the angle sensor indicates that the patient-support deck is in a non-horizontal position, then the actuator is disabled preventing the lock assembly from being unlocked.
Additional features of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of the preferred embodiment exemplifying the best mode of carrying out the invention as presently perceived.